Vibrator absorbing means for an electrical switch

ABSTRACT

An electrical switch having vibration absorbing means to eliminate mechanical and electrical click noises raised therein during a switching action, which comprises an actuating member consisting of an inner member of elastic material supporting one or more movable contact members by direct contact therewith, and an outer member of rigid material securely supporting the inner member. The elastic inner member serves to absorb and restrain the vibrations of the movable contact members, occurring during the switching action.

United States Patent Muraki 51 May 16, 1972 [54] VIBRATOR ABSORBING MEANS FOR AN ELECTRICAL SWITCH [72] Inventor: Shuji Muraki, Hamamatsu-shi, Japan [73] Assignee: Nippon Gakki Selza Kabushlkl Kalsha,

Shizuoka-ken, Japan [22] Filed: May 14, 1971 [2 l Appl. No.: 143,473

[30] Foreign Application Priority Data May 19, 1970 Japan ..4S/48426 52] us. Cl. "zoo/166a [51] Int. Cl. ..H0lh 1/50 58] Field ofSearch .....200/166 H, 166 J;335/l9 3 [56] References Cited 7 UNITED STATES PATENTS. 3,172,972 3/1965 Schleicher.... .i "200/166 H X 3,534,196 10/1970 Ohno ..200/l66 J 2,385,994 10/1945 Johnston. ..200/l66 H X 3,600,543 8/1971 Nakada 200/166 H Primary Examiner-H. 0. Jones A!t0rney-Flynn & Frishauf ABSTRACT An electrical switch having vibration absorbing means to eliminate mechanical and electrical click noises raised therein during a switching action, which comprises an actuating member consisting of an inner member of elastic material supporting one 'or more movable contact members by direct contact therewith, and an outer member of rigid material securely supporting the inner member The elastic inner member serves to absorb and restrain the vibrations of the movable contact members, occurring during the switching action.

3 Claims, 2 Drawing Figures Patented May 16, 1972 FIG! VIBRATOR ABSORBING MEANS FOR AN ELECTRICAL SWITCH This invention relates to electrical switches required to raise less mechanical noises and more particularly, but not for limitation, to key switches for electronic musical instruments.

In an electronic musical instrument, for example, a number of key switches are used to selectively produce musical notes. Each of such key switches has heretofore been comprised of one or more movable contact members of metallic material, and one or more stationary contact members of metallic material corresponding to the movable contact member or members, and an actuator coupled to the movable contact member or members so as to permit the movable contact member or members to be brought into contact with the stationary contact member or members.

The conventional actuator has been made of rigid material such as hard plastics, mainly from the ground that it is required to elevate the controllability.

When the actuator is actuated by a key, one or more movable contact members come into contact with the stationary contact member or members, inevitably generating mechanical and electrical click noises from the contact portions of both members. Such noises are more or less unpleasant to the ears of the player. i

The movable contact member is usually made of resilient metallic material and, when brought into contact with the stationary contact member, it is liable to vibrate, its vibration causing more noises and lasting fairly long. The noises generated at the contact portions of both members are mostly transmitted through the vibrant resilient movable contact member to the actuator and movable-contact-fitting plate without being damped so soon, thus amplifying the noises. Such noises also cause the generation of electrical click sounds detectable in electrical signals. To eliminate such noises, there have been proposed various types of electrical switch, but they are generally bulky or complicated in construction, resulting in increased production cost.

An object of the invention is to provide an electrical switch with less mechanical and electrical noises so as to eliminate the above-mentioned drawbacks.

Another object of the invention is to provide an electrical switch effectively absorbing and restraining the vibration of a movable contact member or members. I

According to one aspect of the invention, the electrical switch comprises one or more movable contact members of electrically conductive material, one or more stationary contact members of electrically conductive material co-operating with the movable contact members, an actuating means bringing the movable contact members into and out of contactwith the stationary contact members, the actuating means including an elastic member supporting the movable contact members, and a rigid member securely holding the elastic member.

Further objects and advantages of the invention will be more apparent from the following description .with reference to the accompanying drawing, in which:

FIG. 1 is aperspective view of an embodiment of the invention; and

FIG. 2 is a magnified view of an actuating member employed in the embodiment of FIG. 1.

In FIG. 1, there is shown a foot-operated key switch for electronic musical instruments. 7

Reference numeral 1 1 denotes a channel-shaped base frame of metal sheet which has a web portion 11a securely supporting an elongated insulating base plate 12 on the inside. On the insulating plate 12 are mounted a plurality of (for example, three as illustrated) movable contact leaf spring members 13 of conductive resilient material such as phosphor bronze which extend parallel to each other in the lengthwise direction of the insulating plate 12 at an equal space from each other and have the rear or base ends fixed on the platelZ through terminal members 14 respectively. On the plate 12 are disposed stationary contact members 15 of electrically conductive material corresponding to the movable contact members 13 in as many pairs as the number of the latter, with the front or free end of each movable contact member 13 interposed between each pair of the stationary contact members. Thus, the movable and stationary contact members 13 and 11$ constitute a multicontact system.

An actuating member 16 supports the movable contact members 13 at the intermediate portions for their actuation. The actuating member 16, as shown in FIG. 2, has an outer member 17 integrally formed of rigid material such as phenol resin laminated plate and, ABS. (acrylonitrile-butadienestyrene) resin plate. The outer member 17 as a whole has a longitudinally elongatedform, with its middle portion 17a forming a similarly elongated and rectangularly looped form so as to encircle an inner member 18 of elastic material such as rubber and foamed plastics. The inner member 18 which may be directly molded into said rectangularly looped portion 17a has a plurality of (for example, three as indicated) rhombic apertures 18a aligned in the longitudinal direction of the actuating member 16 so as to allow the respective movable contact leaf spring members 13 to pass therethrough with both edges of the movable contact member 13 pinched by the inner walls of the rhombic aperture 18a due to the elasticity of the inner member 18.

The actuating member 16 has a lower sliding end portion slidably fitted through an aperture 11b formed in the lower flange portion of the frame 11 and a top stepped end portion 17b closely fitted into an aperture 19a formed at the free end of a plate spring 19, the other end of which is fixed on the upper flange portion 11d of the frame 11, causing its shoulder 16b to abut on the underside of the plate spring 19.

After a key switch is set in place, its assembly is mounted on a musical instrument so as to cause the lower end face of the actuating member 16 to abut on the corresponding footoperated key of the instrument and in consequence the actuating member 16 to be raised against the force of the plate spring 19 so that normally, the movable contact member 13 contacts the upper unit of each pair of the stationary contact members 15. Thus, the depression of the instrument key causes the actuating member 16 to be brought down by the force of the spring 19 with the resultant simultaneous switching action of the movable contact member 13. It will be apparent from the foregoing description that in the electrical switch of the present invention, the movable contact members are supported by the elastic inner member of the actuating means and that, when a shock is caused by the contact of the movable and stationary contact members, the shock and resultant vibration are absorbed and restrained by the elastic inner member, greatly minimizing the occurrence of mechanical and electrical noises.

The electrical switch of the present invention further offers the advantage of reducing manufacturing cost. In the above embodiment, the switch is provided with a plurality of movable and stationary contact members, but the invention may be likewise applied to a key switch employing only one pair of movable and stationary contact members.

The present invention may of course be applied to a manually operated key switch of an electronic musical instrument and further can be practised in other wider fields than the described embodiment by those skilled in the art.

What is claimed is:

1. An electrical switch including at least one movable contact member of electrically conductive material; at least one stationary contact member of electrically conductive material co-operating with said movable contact member, and an actuating member bringing said movable contact member into and out of contact with said stationary contact member to perform a switching action; wherein said actuating member comprises an inner member of elastic material supporting said movable contact member and an outer member of rigid material securely supporting said inner member.

2. The switch according to claim 1 wherein the movable contact member is formed into an elongated leaf spring having its base end fixed, its intermediate portion supported by said actuating member and its free end adapted to contact said stationary contact member.

3. The switch according to claim 1 wherein said outer member has a looped portion securely encircling said inner member which has at least one aperture to allow the movable 5 contact member to pass therethrough with both edges of said movable contact member pinched by the inner walls of the aperture.

gr TED; STATES P TEIW @FFICE CTEHCATE F QRECTWN t May 16; 1972 Patent No. 3 663 776 Ihventor(s) Shu ji MURAKI It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

F '1 In the heading of the patent the Assignee should read -'-N'ipponGakk i Seizo' Kabus-hiki Kai sha Signed end sealed this Zhth day of October 1972.,

(SEAL) v Attest: p q

- w EDWARD MJLETCHER'JR; I v ROBERT GOTT SCHALK Y Attestin'g Officer I I "Commissioner of Patevnce- 

1. An electrical switch including at least one movable contact member of electrically conductive material; at least one stationary contact member of electrically conductive material cooperating with said movable contact member, and an actuating member bringing said movable contact member into and out of contact with said stationary contact member to perform a switching action; wherein said actuating member comprises an inner member of elastic material supporting said movable contact member and an outer member of rigid material securely supporting said inner member.
 2. The switch according to claim 1 wherein the movable contact member is formed into an elongated leaf spring having its base end fixed, its intermediate portion supported by said actuating member and its free end adapted to contact said stationary contact member.
 3. The switch according to claim 1 wherein said outer member has a looped portion securely encircling said inner member which has at least one aperture to allow the movable contact member to pass therethrough with both edges of said movable contact member pinched by the inner walls of the aperture. 